Vascularized porous metal orthopaedic implant devices

ABSTRACT

An osteoconductive vascularized porous metal implant device and method for implanting the vascularized device are described herein. The vascularized implant device comprises an implant which is porous titanium, tantalum or other metal which is biocompatible with the mammalian body and at least one vascular conduit which connects the porous implant to an animal vasculature, such as a human vascular system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Application No. 61/693,355, filedAug. 27, 2012, and Application No. 61/749,656 filed Jan. 7, 2013 whichare hereby incorporated herein by reference in their entirety.

FIELD

The present application relates to medical devices and methods, and moreparticularly, to vascularized porous metal orthopedic implants.

BACKGROUND

In orthopedic surgery, bones are often fused together to prevent pain,improve function, and heal injuries. In settings of impaired bloodsupply, massive bone loss, or complicated trauma, techniques such asbone grafting or implanting metal are used to facilitate fusion orreconstruction. However, bone grafts have limitations of strength andavailable amounts of donor bone. Metal implants are also imperfectbecause if they are not securely fixed in living bone, they go ontofatigue and failure. In addition, both bone grafting or implanting canbe problematic when there is inadequate blood supply to the repairedregion including the bone or implant. Insufficient blood supplyincreases the risk of infection and limits the amount of bone formationin and at the interface of the implant with the bone (osteogenesis).

Some have tried vascularized bone grafting where blood is supplied byveins or conduits naturally forming part of the bone graft. Thistechnique uses natural/actual bone with an attached blood vessel wherethe bone is harvested from the patient or donor, and then the harvestedbone is used to fuse or reconstruct bones. It is known that theincreased blood supply speeds healing, reduces infection, and increasesstrength. Unfortunately, however, current vascularized bone grafts mustbe harvested from the patient, increasing morbidity, lengtheningrecovery time, and increasing surgical complexity, such as infectionrisk. In addition, the number, size and shape of current vascularizedbone grafts are limited. Lastly, these grafts are not usually taken fromanother animal or person due to immunologic graft-rejection issues.

As can be seen, there is a need for a system that combines the strengthof a metal implant with a more effective blood supply than the supplyprovided by native vascularized bone implant or graft. It may bedesirable to minimize large avascular regions in a bone graft or implantwhich can harbor bacteria. It also may be desirable to avoid the riskand disadvantages which currently exist with a massive bone harvest withlater use of the bone harvest as a bone graft or implant. Even further,even if a bone harvest could be readily used without regard to problemsassociated with the act of harvesting bone, there is a need andadvantages to providing an implant that can be made in a plurality ofshapes and sizes that would not be available or at least readilyobtained from a harvest of natural bone from a patient.

The advantages of a vascularized porous metal implant device include (1)the device not being limited by size or shape as compared to naturallyharvested bone, (2) there is not a breakdown of the metal implant, (3)the device promotes bone growth into the core of the implant across afusion gap between two pieces of bone being fused or connected and (4)the device lowers infection rate of implant by increasing bloodcirculation throughout the implant. These and other advantages willbecome apparent from the discussion set forth below.

SUMMARY

In one form, an osteoconductive vascularized porous metal implant deviceand method for implanting the vascularized device are described herein.The vascularized porous metal implant device comprises an implant whichis porous titanium, tantalum or other metal which is biocompatible withthe mammalian body and at least one vascular conduit which connects theporous metal implant to a mammalian vasculature, such as a humanvascular system. The osteoconductive vascularized porous metal implantdevice is implanted into a host in need thereof, connected to thevascular system, and is used for reconstruction of bone defects or jointdefects by removing diseased or injured bone(s) and attaching theimplant which then promotes bone healing by bone fusion growth into theporous metal implant by virtue of exposing bone to blood being conveyedinto the metal implant while also reducing fatigue and implant failure.

According to one form, the metal implant has a porosity that providesinternal voids which form at least about 50 volume percent of theimplant and preferably from about 70 to about 80 volume percent of theimplant. At least one vascular conduit effects blood flow into theporous metal implant by having the vascular conduit extend into andbelow the outer surface of the metal implant to effect blood flow fromthe vascular system of the host who receives the implant device into theinternal portions of the porous metal implant. This provides blood flowinternal to the porous metal implant, and as a result, effects exposureof blood to bone interfacing with the implant and effects bone growthinto the pores of the implant for improved strength and durability ofthe bone graft created by the implant connecting or interfacing twosections of bone. According to one form, it is hypothesized that bloodflows through the porous implant at least as a result of capillaryaction.

In one form, after grafting the vascularized porous metal implant deviceinto the reconstracted area, the enhanced blood flow into the interfacebetween the bone and implant increases bone growth internal to theporous metal implant and improves the strength of the graft afterinsertion thereof by at least about 4×, and even more than 16× ascompared to implanting the same porous metal implant which has not beenvascularized for increased blood flow internal to the porous implant.According to one form, this increased blood flow is at least 10× andeven more than 100× the blood flow internal to the porous implant ascompared to known porous metal implants that have not been connected tothe vascular system as described herein.

According to one form, the porous titanium or porous tantalum can befoam implants, for example, comprising pores of about 300 nm to about1300 nm depth and breadth of each pore, preferably about 400 nm to about800 nm, more preferably about 700 nm, which are commercially availablefrom Zimmer, Inc., Warsaw, Ind., USA. In another important aspect, thevascular conduit is made from polytetrafloro ethylene (PTFE) which hasbeen extruded and which is commercially available from Atrium Medical,Hudson, N.H., USA. Other polymeric materials may also be suitable forthe vascular conduit including polyethylene terephthalate and otherwoven polyesters. The diameter of these conduits is in the range of fromabout 3 mm to about 9 mm.

In one form, the number of vascular conduits, positioning the conduitsand the number, size and volume of the pores are effective to provide ablood flow that is at least 10× and can supply even more than 100× bloodflow internal to the porous implant as compared to the same porous metalimplants that have not been connected to the vascular system asdescribed herein. According to one form, the number of vascularconduits, positioning of the conduits, and the number, size and volumeof the pores are effective to provide an enhanced blood flow into theinternal voids of the metal implant and the interface between the boneand implant. After grafting the vascularized porous metal implant deviceinto the reconstructed area bone growth internal to metal implant, bloodflow is increased and improves the strength of the graft after insertionby at least about 4×, and even more than 16× after about 4-6 weeks ascompared to implanting the same metal implant which has not beenvascularized for increased blood flow internal to the porous implant.

In accordance with one form, the increased blood flow into the implantis important in respect to large implants. The risk of catastrophicimplant failure increases with the size of the implant because bone hasdifficulty in achieving durable and/or strong connection between a largeimplant and existing bone because the ratio of the surface area of thebone/implant interface to the overall size of the implant is low. Porousimplants increase the surface area, but bone ingrowth is still limitedto the periphery of the implant. However in a small implant, the ratioof the surface area of the bone/implant interface to the overall size ofthe implant is larger. There is more peripheral surface area to allowfor ingrowth and increase stability. In fact, if the small implant isporous, bone ingrowth from the edges may meet in the center, effectivelycompletely incorporating the implant. However, even in porous implants,the depth of bone ingrowth is not more than several millimeters andimplants with a radius of greater than approximately 3 mm will notachieve ingrowth into the center of the implant.

The lack of such ingrowth, particularly in large implants, increases therisk of implant failure taught in the prior art. In one form, using thevascularized, porous implant device described herein overcomes thelimitation of size and shape of implants because of relatively highmechanical loading or high torque applications, and/or large implants.Hence in an important aspect, when the ratio of the surface area betweenthe bone and implant interface to the overall size of the implant isless than about 0.75 use of the vascularized implant device isparticularly useful in providing the increased strength and blood flowdescribed herein.

Also described herein is a method of performing orthopedic surgery whichincludes implanting the porous metal implant and connecting at least onevascular conduit to the vascular system of the host.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a top perspective view of a four corner implant device asaffixed to various wrist bones;

FIG. 1b is a side perspective view of the implant device of FIG. 1 a;

FIG. 2 is a perspective view of another form of an implant device;

FIG. 3a is a perspective view of an implant device inserted in a wristof a patient;

FIG. 3b is an enlarged view of the implant device of FIG. 3 a;

FIG. 4a is a perspective views of a hexagonal cross sectional form of animplant device;

FIG. 4b is an enlarged view of the implant device of FIG. 4 a;

FIG. 5 is a side perspective view of one form of a portion of areplacement joint being inserted into a host bone along with aninstrument fused in the process of insertion;

FIG. 6a is a perspective view of one form of a chimeric implant devicebeing inserted between a host bone and a graft bone; and

FIG. 6b is a perspective view of the chimeric implant device of FIG. 6aafter the host bone and graft bone have been brought together.

DETAILED DESCRIPTION

The following detailed description is of currently contemplated modes ofcarrying out exemplary embodiments of the present application. Thedescription is not to be taken in a limiting sense, but is made merelyfor the purpose of illustrating the general principles.

In one form, a porous implant device is provided which includes a rigid,unbendable, non-flexible, porous implant, such as a porous metalimplant, and at least one biocompatible conduit. The implant isnon-flexible, but also exhibits a modulus of flexiblity about the sameas human bone. The porous metal implant may be made from a variety ofdifferent materials that are suitable for implantation and use, such asin mammals. For example, in one form, the porous metal implant includesat least one metal selected from the group consisting of poroustitanium, porous tantalum or metal-alloy comprising porous titanium ortantalum implants. Other materials besides metals may also be utilizedwhich can be manufactured with pores and/or channels to permit bloodflow and/or bone growth through at least a portion of the implant. Inone preferred form, the porous implant has sufficient strength tosupport bones in a desired implant location. For example, an implantnear a hip joint may be desired to have a higher strength than animplant in other locations. Finally the implant is more stable and doesnot break down relative to vascularlized bone harvested from the host orallograft bone (from a dead person) over the same comparative timeperiods.

According to one form, the porous implant, such as made from titanium ortantalum, can be foam implants. For example, the foam implants maycomprise pores and/or channels that are about 300 nm to about 1300 nm indepth and breadth of each pore, preferably about 400 nm to about 800 nm,more preferably about 700 nm. Such implants are commercially available,such as from Zimmer, Inc. Such implants may be suitable for achievingbony ingrowth. The rigid, non-flexible material described above,provides structural strength and stability within the implant region ofthe bone. Additionally, in one form, the pores described above arethroughout the entire implant, and not limited to the surface.

There are numerous processes for production of porous metal implants.For example, in one form, a reticulated vitreous carbon network isprepared using a chemical vapor deposition process to layer elementalmetal onto the underlying carbon structure. Such processes are used byZimmer.

Other processes may involve some form of forging, three-dimensionalprinting (3DP) or other forms of manufacture. Three-dimensional printingcan be used to optimize or customize the design of efficient channels.Three-dimensional printing functions by repeated deposition of powderedmaterial in thin layers and printing of a binder material on each powderlayer to selectively bind the powder deposited in that layer. Thisprocess is repeated layer after layer until the whole three-dimensionalpart is completed according to sliced data from a CAD model. A CAD modeldesign is converted into alternative computer language files, which issliced into thin cross-sectional layers and sintered at a range of 1200°to 1500° C. The use of 3DP provides a tool for designing well-definedchannels for circulation throughout the implant in a sterileenvironment.

Alternatively, vascular channels within an implant can be drilled orcut, or incorporated in the initial forging. The sizes of the channelsare variable in size, and will be created in a branching, reticularfashion to mimic native nutrient arteries. The branching patterns arebased on studies of nutrient arteries in bone specimens as well on knownfractal mathematical relationships of vessel arborization. In one form,the range is about 0.5-5 mm in diameter.

The biocompatible conduit, such as in the form of a vascular conduit,may be made from a variety of different materials in a variety ofdifferent sizes, lengths, gauges and the like. For example, in one form,the vascular conduit may be a biocompatible polymer conduit such as aPTFE (polytetrafluoroethylene) vascular conduit, such as made under thename GORETEX®, to impart vascularity throughout the implant. Thevascular conduit can be attached to the implant by a number of ways, byway of example, gasket, O-ring, stitching, staples, glue, and otherattachment means known in the art.

In one form, the polymeric vascular graft functions as a conduit forattaching blood vessels to one another and/or to the implant. Thisconduit allows connection of the porous metal implant to a local bloodvessel to allow vascular ingrowth. In one form, the vascular conduit mayprovide blood flow into the porous metal implant by having the vascularconduit extend into and below an outer surface of the porous metalimplant. Such a combination may provide a greater blood supply andprogenitor cells that form bone at least partially though and around theimplant, thereby facilitating faster healing, healing of larger defects,and improved immunologic protection through greater contact with thehumeral immune system in an animal or human patient. In addition, in oneform, such a combination may eliminate morbidity of bone graft harvestand expands the size and shape of grafts available.

Implants can be provided with the polymeric vascular conduitpre-attached, but depending on the configuration, providing implantswith multiple access points for graft attachment as well as a clamp andO-ring connection may allow for intraoperative vascular graft placementafter the structural metal component has already been implanted. Thisversatility can allow the flexibility needed in situations of aberrantanatomy or when the initial operative plan encounters difficulties. Suchequipment can come in a prepared kit with the implant that includes theinstrumentation needed both to place the implant as well as tools tomodify it such as heavy-duty bolt cutters or snips for fashioning theimplant in situ, polymeric conduits of varying dimensions to accommodatediffering host vessel calibers, microsurgical instruments for preparingthe anastomosis between the implant and the host vasculature, O-ring,gasket, sleeve-and-stem, and bidirectional couplers used to affix thepolymeric conduit to different locations in the implant, chemical andbiological additives such as heparin, bone morphogenic protein,procollagen, vascular endothelial growth factor, and the previouslynamed growth factors to aid in preparing the anastomosis and priming theimplant for vascular invasion and osseous integration. Many of theseinstruments may be packaged in the same container for sterileprocessing, though several of the implantables such as the grafts andthe additives such as the chemicals and growth factors may comeseparately packaged in sterile packaging or “peel-packed” for use asneeded during the surgical procedure.

Further, the vascularized implant device may come in the form of a kit.The kit may include one or more porous implants, one or more vascularconduits and at least one instrument for assisting in installation ofthe vascularized implant device. For example, the kit may include aplurality of differently sized or shaped porous implants. Similarly, thekit may include a plurality of different vascular conduits which mayhave different lengths, gauges, diameters and the like so the kit may beconfigured for the specific use.

It should be noted that the porous implant may be manufactured to have avariety of sizes and shapes. For example, such shapes may include, butare not limited to, rings, barbells, square, rectangular, wedge-shaped,irregular shaped, and the like. The actual shape may be prepared inaccordance with the desired use. For example, different bone implantlocations necessitate different shapes and configurations.

Described also is a method for generating implants of a specific sizeand shape for various applications. Libraries of bone specimens exist inseveral locations that have been used for anthropological and medicalresearch. Bones from these libraries can be evaluated usingcross-sectional imaging such as computerized tomography for attributesrelating to their size and shape as well as the patterns of intraosseousvascular channels. This data may be used along with computer aideddesign techniques to program 3DP or other fabricating machines toproduce implants that mimic these properties. Further, the patient's ownanatomy may be used in a similar fashion as their limb or a portion oftheir spine may be imaged and the data from that used to fashioncustom-made implants.

The porous metal implant devices described herein may be used withvascular conduit for arthrodesis, joint fusion, small bone alignment(such as intercarpal fusion, foot and ankle fusion, wrist fusion, kneefusion, etc.) grafting large segments together including an abovecritical size defect replacement with an arthroplasty (such as oncologichip and/or knee prosthesis). Also described herein are methods ofrevascularization and reconstruction of bones with compromised bloodsupply such as scaphoid or femoral head avascular necrosis; methods ofreconstruction with delivery of antibiotics from the blood stream andthroughout the recipient site implants for reconstruction of criticaldefects in the setting of oncologic resection, trauma, and massiveinfection.

The porous metal implant may be configured to provide the structuralrigidity and support to facilitate bone fusion or healing. The vascularchannels and/or pores within the metal implant improve blood flow fromthe center of the implant to the periphery in a fashion similar toliving bone.

In one form, coating portions of the vascular channels of the porousimplant and/or the vascular conduit with specific growth factors such asVEGF (Vascular Endothelial Growth Factor), antibiotics or otherinfection inhibiting or healing medicaments, or hydroxyapatite which canencourage blood vessel formation and differentiation of progenitor cellspreferentially into osteoblastic cells that form bone.

Further, in one optional form, the implant device may also include oneor more further vascular conduits which may be used as an outlet conduitfrom the implant. In other words, as blood flows from an inlet vascularconduit and through the porous implant, a further conduit may be provideto allow blood to be removed from the porous implant. Such a system canbe used in the case of excess blood flow, to allow blood which hasalready contacted the bone to pass through, and the like. The outletconduit may be connected to further vasculature and/or simply lead awayfrom the implant device to other locations.

In addition to the benefits of improving fusion mechanics, thecombination of features may be especially advantageous in various areasof the body. For example, areas such as the wrist which are relativelysubcutaneous may be suitable for the implant device. Many fusionimplants, especially those for total wrist fusion, lie external to thebone and create problems with their prominence, often necessitatingsecondary surgeries for implant removal. The described disclosureminimizes the need for secondary surgeries by fusing throughout the hostbone.

Partial wrist arthrodesis with scaphoid excision is a common surgicalprocedure used to address arthrosis and pain created by various types ofligamentous instability. Once soft-tissue procedures have failed andearly arthrosis and pain have developed, this procedure offers adurable, stable wrist that allows for pain-free activity. While thisobviously has some limited motion compared with the uninjured wrist, ithas much more motion than the definitive option of total wrist fusion.This makes it very appealing to surgeons and patients.

Perhaps the greatest complication with certain surgeries is failedfusion (pseudarthrosis). Most surgeons use a dorsal approach to thewrist and the hardware is all placed dorsally. In addition to the issuesof symptomatic hardware, this dorsal placement can also cause the carpalbones to gap open on the volar surface, which can cause pseudarthrosis.

Referring to FIG. 1a , one form of an implant device 10 is shown. Theimplant device 10 is generally a four-corner fusion implant which may besuitable for pseudarthrosis. The implant device 10 includes a porousmetal implant 12 and a vascular conduit 14. A first end 16 of thevascular conduit is operably coupled to the implant 12 while a secondend 18 is configured to be operably couple to a vascular system (notshown).

As seen in FIGS. 1a and 1b , the implant 12 includes four posts 20, 22,24, 26 which may be configured for coupling to various portions of theanatomy, such as the lunate 28, triquetrum 30, capitate 32, and hamate34 bones. The implant 12 may be inset into the four bones 28, 30, 32,34, once they are prepared for fusion with high-speed bur (not shown). Aguide jig (not shown) may be used to bur a trough for placement of theimplant in a press-fit fashion. This press-fit and friction created bydeliberately slightly undersizing the radius of the burred trough may beused to provide stability. In addition, because the implant isintraosseous, the moment arm is shortened, and the stability increased.

Referring to FIG. 2, a further implant device 40 is shown. The device 40includes an implant 42, such as a porous metal implant, and a vascularconduit 44. As seen in FIG. 2, the implant 42 has a different shape thanimplant 10 shown in FIG. 1a . Implant 40 has a different shape forcoupling different bones such as bone 46 and bone 48. In this regard,the implant 42 is generally wedge shaped to accommodate differentanatomical shapes.

For example, implant device 40 may be used to treat avascular necrosisof the proximal pole. The implant device 40 is connected with the radialartery using a microvascular end-to-side anastamosis in the same fashionas is currently employed with vascularized bone autografting. In oneform, both the conduit 44 and the implant 42 may be treated withvascular endothelial growth factor (VEGF), Epidermal growth factor(EGF), prostaglandin E2 (PGE2), Insulin-like growth factor (IGF 1 or 2),or Osteoprotegerin (OPG), optionally combined with hydroxylapatite (HA),to aid in the revascularization of the scaphoid. The same implant andmethod may be employed in the treatment of avascular necrosis of thelunate (Kienbock's disease) and scaphoid (Preisser's disease).

Referring now to FIGS. 3a and 3b , a further form of device is shown asimplant device 50. Implant device 50 include implant 52, such as aporous metal implant, and a vascular conduit 54. As seen in FIGS. 3a and3b , the implant 52 is generally barbell shaped and may be used withvarious anatomies, such as in a wrist area 56. The implant 52 is barbellshaped to operably couple at least two bones.

With respect to scaphoid nonunion and malunion, the retrograde bloodsupply of the scaphoid and unique shape predispose it to both avascularnecrosis of the proximal pole and collapse into what is termed a“humpback” deformity. Numerous surgical techniques have been describedto restore the length and bone stock of the scaphoid as well as toincrease vascularity to the proximal pole.

Much in the same way that a vascularized bone autograft is used forscaphoid nonunions with humpback deformity, this technique describes animplant to restore the alignment and blood supply of the scaphoid,wherein a porous titanium foam implant is machined to fit the scaphoid,such as in a dumbell shape shown in FIGS. 3a and 3b , and implantedusing a volar surgical approach. This allows reduction of the fractureand eliminates one of the primary difficulties encountered with currentfixation methods-joint penetration with the hardware.

A further form of device is shown in FIGS. 4a and 4b , such as in theform of implant device 60. Implant device 60 include implant 62, such asa porous metal implant, and a vascular conduit 64. As seen in FIGS. 4aand 4b , the implant 62 is generally in the form of a prism with ahexagonal cross-section. In this regard, implant device 60 may be usedin a variety of anatomies, such as a wrist, to fuse at least twoadjacent carpal bones 66, 68. The carpal bone surfaces may be preparedin the same fashion as described above and a trough is burred acrossthem into which the implant is press-fit. In one form, the implant 62can be provided in a variety of lengths and cut to measure in theoperating room with a bolt cutter or rod cutter.

In one aspect, provided herein are expanded applications such asbiocomposite implants, chimeric implants and xenochimeric implants. Theaddition of direct vascular access throughout the porous implantsincreases the applications of the chimeric implant technology. Theporous architecture allows for vascular access at the periphery bydiffusion, but prior to the addition of a more direct vascular conduit,the size of the implants that could be used was limited. An applicationof porous titanium foam as a scaffold for autologous chondrocyteimplantation into a joint defect has been described in the prior art.This application however is limited to defects small enough to allowdirect diffusion of the host blood supply through the implant. By addinga robust and dedicated vascular supply described herein, compositeimplants of larger size could be constructed.

A further example is shown in FIG. 5. In this form, an implant device 70is provided with a first porous implant 72 and a second porous implant74 coupled together via a connecting structure 76. It should be notedthat while the first implant 72 and the second implant 74 are shown asseparate components separated by the connecting structure 76, suchcomponents may take the form of a single, integral structure, such as asingle porous structure. The implant device 70 further includes avascular conduit 78. While FIG. 5 illustrates the conduit 78 couple tothe connecting structure 76, it should be noted that the conduit mayalso and/or alternatively coupled to the first implant 72 and/or thesecond implant 74. Further, multiple conduits may also be used. Thedevice 70 may also be in the form of a kit, whereby additional sizes andshapes of conduits, tools, accessories and the like, as represented bybox 80.

In one form, the implant device 70 may be suitable for a total distalfemur or distal humerus replacement for unipolar arthritis orpostoncologic reconstruction. A similar end-to-side anastamosis into thefemoral or brachial ateries could supply the implant distally for moredirect diffusion into attached autologous chondrocytes. This has anadvantage over currently used techniques such as fresh-frozenosteochondral allografting as there is no immunigenic response and thereis no graft resorption.

Yet another example of the implant device is shown in FIGS. 6a and 6b .In this form, an implant device 90 is shown having an implant 92, suchas in the form of a generally cylindrical implant, and at least onevascular conduit. As shown in FIGS. 6a and 6b , the device 90 mayinclude a first vascular conduit 94 operably coupled to a first portionof a vascular system and/or a second vascular conduit 96 operablycoupled to a second portion of a vascular system.

Such a device 90 may be used in a variety of anatomies. For example, inone form, the device 90 may be used as part of a joint or limbtransplantation. According to one form, the implant 92 can be used toaffix skeletal elements 100 of a transplanted limb to a host limb 102which are then brought together, as represented by arrows 104, 106. Byallowing osteocyte ingrowth of both the host and donor osteocytes intothe same implant, such as shown at 108, a chimeric biocomposite implantis created, as shown in FIG. 6b . Per current research inimmunomodulation for joint allotrans-plantion, this has the potential toinduce tolerance in the host by aiding in the creation of a chimericorgan by modulating the rate of host-donor interface.

It should be understood, of course, that the foregoing relates toexemplary embodiments of the invention and that modifications may bemade without departing from the spirit and scope of the invention as setforth in the following claims. By way of example, the present inventionincludes modifications such as drill holes or grommets for augmentedfixation with screws through host bone, anti-microbial coating, andpre-seeding vascular channels with endothelial cells and growth factors.It should also be understood that ranges of values set forth inherentlyinclude those values, as well as all increments between.

What is claimed is:
 1. A vascularization device which is configured to increase blood circulation to a porous metal implant to effect an increase in bone growth internal to the device after implantation into a host, the device comprising: the porous metal implant, which is biocompatible with the mammalian body, and is configured to provide structural rigidity between adjacent bone portions at the time of implantation, the metal of the implant selected from the group consisting of porous titanium, porous titanium-alloy, porous tantalum, porous tantalum-alloy, and combinations thereof, the metal implant having pores of about 300 nm depth and breadth, the porous metal implant being configured to provide a ratio of bone interface surface area to implant interface surface area which is less than about 0.75 after implantation; at least one implantable inlet vascular conduit comprising a biocompatible polymer and which is arranged and configured to supply blood into the implant and to connect the porous implant to a mammalian vascular system when the device is implanted, the at least one implantable inlet vascular conduit comprising a tube having a diameter in the range of from about 3 mm to about 9 mm, the biocompatible polymer comprising polytetrafluoroethylene; and at least one implantable outlet vascular conduit comprising a biocompatible polymer and which is configured to couple the implant to a second portion of the vascular system and transmit blood from the implant to the second portion of the vascular system after implantation, the at least one implantable outlet vascular conduit comprising a tube having a diameter in the range from about 3 mm to about 9 mm, the biocompatible polymer comprising polytetrafluoroethylene, the porous metal implant having a rigid structure with internal voids throughout an interior portion of the porous metal implant, and the internal voids forming at least 50% by volume of the implant, the porous metal implant configured to permit at least one of blood flow and bone growth into the internal voids, and the implantable inlet and the outlet vascular conduits and the porous metal implant configured and arranged to provide blood flow into and from the porous metal implant after implantation, the at least one implantable inlet vascular conduit extending within the porous metal implant and below an outer surface of the porous metal implant and configured to effect blood flow below the outer surface of the porous metal implant and outwardly to a periphery of the porous metal implant after implantation, wherein the at least one implantable inlet vascular conduit and the at least one implantable outlet vascular conduit include at least one attachment selected from the group consisting of a gasket, O-ring, stitching, staples, glue, and combinations thereof, wherein the attachment is configured to attach the at least one implantable inlet vascular conduit and the at least one outlet vascular conduit to the mammalian vascular system. 